Critical technical elements of state bioassessment programs: a process to evaluate program rigor and comparability

We developed a systematic process to evaluate state/tribal bioassessment programs to provide information about the rigor of the technical approach. This is accomplished via on-site interviews to produce an evaluation that assigns one of four levels of rigor as an outcome. Level 4 is the most rigorous and reflects a technical capacity to accurately determine incremental condition and support management programs. The remaining three levels are less able to assess incremental condition and are appropriate for only some management support needs. Accurately determining impairment and diagnosing pollution-specific stressors are fundamental tasks that states/tribes must accomplish to provide management support. This goal is fulfilled to varying degrees by most states/tribes. The evaluation employs a checklist and a sliding scale of rigor for 13 technical elements. Feedback is provided to each state/tribe via a technical memorandum that describes the technical components of the monitoring program, highlights strengths, and recommends improvements for specific technical issues. This can be used to refine the bioassessment and monitoring programs to better support management programs. The results of 14 state/tribal evaluations are included here. The majority (nine states, one tribe) revealed that most operate at level 2 with developmental activities that will elevate the level of program rigor already underway. Two states operate level 4 programs and each have numeric biocriteria and refined designated uses in their water quality standards. This is the ultimate goal of the process of engaging states in the development of bioassessment programs in the U.S.     

A storm event-based approach to TMDL development

It is vitally important to define the critical condition for a receiving water body in the total maximum daily load (TMDL) development process. One of the major disadvantages of using a continuous simulation approach is that there is no guarantee that the most critical condition will be covered within the subjectively selected representative hydrologic period, which is usually several years depending on the availability of data. Another limitation of the continuous simulation approach, compared to a design storm approach, is the lack of an estimate of the risk involved. Because of the above limitations, a storm event-based critical flow-storm (CFS) approach was previously developed to explicitly address the critical condition as a combination of a prescribed stream flow and a storm event of certain magnitude, both having a certain frequency of occurrence and when combined, would create a critical condition. The CFS approach was tested successfully in a TMDL study for Muddy Creek in Virginia. The present paper reports results of a comparative study on the applicability of the CFS approach in Taiwan. The Dy-yu creek watershed in northern Taiwan differs significantly from Muddy Creek in terms of climate, hydrology, terrain, and other characteristics. Results show that the critical condition for different watersheds might be also different, and that the CFS approach could clearly define that critical condition and should be considered as an alternative method for TMDL development to a continuous simulation approach.     

A batch study on the bio-fixation of carbon dioxide in the absorbed solution from a chemical wet scrubber by hot spring and marine algae

Carbon dioxide mass transfer is a key factor in cultivating micro-algae except for the light limitation of photosynthesis. It is a novel idea to enhance mass transfer with the cyclic procedure of absorbing CO(2) with a high performance alkaline abosorber such as a packed tower and regenerating the alkaline solution with algal photosynthesis. Hence, the algae with high affinity for alkaline condition must be purified. In this study, a hot spring alga (HSA) was purified from an alkaline hot spring (pH 9.3, 62 degrees C) in Taiwan and grows well over pH 11.5 and 50 degrees C. For performance of HSA, CO(2) removal efficiencies in the packed tower increase about 5-fold in a suitable growth condition compared to that without adding any potassium hydroxide. But ammonia solution was not a good choice for this system with regard to carbon dioxide removal efficiency because of its toxicity on HSA. In addition, HSA also exhibits a high growth rate under the controlled pHs from 7 to 11. Besides, a well mass balance of carbon and nitrogen made sure that less other byproducts formed in the procedure of carboxylation. For analysis of some metals in HSA, such as Mg, Mn, Fe, Zn, related to the photosynthesis increased by a rising cultivated pH and revealed that those metals might be accumulated under alkaline conditions but the growth rate was still limited by the ratio of bicarbonate (useful carbon source) and carbonate. Meanwhile, Nannochlopsis oculta (NAO) was also tested under different additional carbon sources. The results revealed that solutions of sodium/potassium carbonate are better carbon sources than ammonia carbonate/bicarbonate for the growth of NAO. However, pH 9.6 of growth limitation based on sodium was lower than one of HSA. The integrated system is, therefore, more feasible to treat CO(2) in the flue gases using the algae with higher alkaline affinity such as HSA in small volume bioreactors.     

The influence of radical architecture on cadmium bioaccumulation in the black mangrove, Avicennia germinans L

Two groups of Avicennia germinans plants with differences in the radical architecture were exposed under hydroponic conditions to 95ppm of cadmium (Cd) for a period of 24h. Later, Cd concentration in roots, stems and leaves was determined by graphite furnace atomic absorption spectrophotometry. Our results showed that, for both groups of plants, the roots accumulated higher concentration of Cd as compared to stems and leaves, though, the plants of group B displayed enhanced radical architecture, better growth performance, and lower Cd concentration as compared to plants of group A. In contrast, low values of leaves/roots Cd transportation index, and bioaccumulation factor were found in plants of group B. These results suggest that the higher radical architecture developed in plants of group B might better adjust the uptake of Cd as a result of an integrated network of multiple response processes for instances, production of organic acids, antioxidative replay, cell-wall lignification and/or suberization. Further studies will be focused in understanding the role of the radical system in mangrove plants with the rhizosphere activation and root adsorption to soil Cd under natural conditions.     

Aerobic degradation of di- and trichlorobenzenes by two bacteria isolated from polluted tropical soils

Two polychlorinated biphenyl (PCBs)-degrading bacteria were isolated by traditional enrichment technique from electrical transformer fluid (Askarel)-contaminated soils in Lagos, Nigeria. They were classified and identified as Enterobacter sp. SA-2 and Pseudomonas sp. SA-6 on the basis of 16S rRNA gene analysis, in addition to standard cultural and biochemical techniques. The strains were able to grow extensively on dichloro- and trichlorobenzenes. Although they failed to grow on tetrachlorobenzenes, monochloro- and dichlorobenzoic acids, they were able to utilize all monochlorobiphenyls, and some dichlorobiphenyls as sole sources of carbon and energy. The effect of incubation with axenic cultures on the degradation of 0.9 mM 1,4-dichlorobenzene, 0.44 mM 1,2,3- and 0.43 mM 1,3,5-trichlorobenzene in mineral salts medium was studied. Approximately, 80-90% of these xenobiotics were degraded in 200 h, concomitant with cell increase of up to three orders of magnitude, while generation times ranged significantly (P<0.05) from 17-32 h. Catechol 1,2-dioxygenase and catechol 2,3-dioxygenase activities were detected in crude cell-free extracts of cultures pre-grown with benzoate, with the latter enzyme exhibiting a slightly higher activity (0.15-0.17 micromolmin(-1) mg of protein(-1)) with catechol, suggesting that the meta-cleavage pathway is the most readily available catabolic route in the SA strains. The wider substrate specificity of these tropical isolates may help in assessing natural detoxification processes and in designing bioremediation and bioaugmentation methods.     

QSARs for the toxicity of polychlorinated dibenzofurans through DFT-calculated descriptors of polarizabilities, hyperpolarizabilities and hyper-order electric moments

DFT-B3LYP method with 6-31G(**) basis set was employed to fully optimize the electronic structures of 135 polychlorinated dibenzofurans and parent compound, namely dibenzofuran. It was demonstrated that polarizability anisotropy and mean polarizability could change sensitively and systematically with chlorine number and substitution pattern. And new quantitative structure-activity relationships (QSARs) focused on the binding affinities of aryl hydrocarbon receptor (AhR), aryl hydrocarbon hydroxylase (AHH) and 7-ethoxyresorufin O-deethylase (EROD) induction potencies of PCDFs were developed. It was concluded that polarizability anisotropy in conjunction with hyperpolarizabilties and hyper-order electric moments, e.g. octupole moments could well interpret the variation of toxicity of different congeners and dispersion interaction should be the leading form among various interactions. Although the terms of hyperpolarizabilities and hyper-order electric moments were not the same significant ones as polarizability anisotropy, the long-range interactions characterized by them should not be ignored in explaining the toxicity.     

Evaluation of nitrification inhibitor 3,4-dimethyl pyrazole phosphate on nitrogen leaching in undisturbed soil columns

The application of nitrogen fertilizers leads to various ecological problems such as nitrate leaching. The use of nitrification inhibitors (NI) as nitrate leaching retardants is a proposal that has been suggested for inclusion in regulations in many countries. In this study, the efficacy of the new NI, 3,4-dimethyl pyrazole phosphate (DMPP), was tested under simulated high-risk leaching situations in two types of undisturbed soil columns. The results showed that the accumulative leaching losses of soil nitrate under treatment of urea with 1.0% DMPP, from columns of silt loam soil and heavy clay soil, were 66.8% and 69.5% lower than those soil columns tested with regular urea application within the 60 days observation, respectively. However, the losses of ammonium leaching were reversely increased 9.7% and 6.7% under the former treatment than the latter one. Application of regular urea with 1.0% DMPP addition can reduce about 59.3%-63.1% of total losses of inorganic nitrogen via leaching. The application of DMPP to urea had stimulated the inhibition effects of DMPP on the ammonium nitrification process in the soil up to 60 days. It is proposed that the DMPP could be used as an effective NI to control inorganic N leaching losses, minimizing the risk of nitrate pollution in shallow groundwater.     

Bioavailability to grains of rice of aged and fresh DDD and DDE in soils

DDT had been widely used around the world before 1980s and is still under production and use for non-agricultural purposes in China. Because of their special physicochemical properties, p,p'-DDT and its main metabolites, p,p'-DDD and p,p'-DDE, accumulated and persisted in the environment, presenting potential menace on biota. A green-house study was conducted to determine the bioavailability of p,p'-DDD and p,p'-DDE to grains of rice and the influences of traditional Chinese farming practices on their bioaccumulation. Paddy rice and dry rice were grown in submerged paddy soils and non-submerged upland soils, respectively. Two types of soil, Hydragric Anthrosols (An) and Hydragric Acrisols (Ac), were employed. Bioaccumulation factors (BAFs) of DDE ranged from 0.67 for rice grown in non-submerged An to 0.84 in submerged An in the control group, whilst BAFs were all below 0.04 in experimental groups. BAFs of DDD varied from 1.39 for submerged An to 2.26 for submerged Ac in original soils. In contrast, BAFs were between 0.05 for non-submerged Ac and 0.08 for submerged An in DDD-contaminated soils. Flooding seemed to have two contradictory effects on the DDE/DDD accumulation by rice: on one hand, it made the pollutants more mobile and bioavailable; while on the other hand, it enhanced the degradation and binding of POPs. Adding rice straw to the soils protected DDE from being taken up yet promoted DDD accumulation by rice. Furthermore, the distinct inorganic component of the soils might also play an important role in the environmental activities of POPs.     

The impact of UV-B and sulphur- or copper-containing solutions in acidic conditions on chlorophyll fluorescence in selected Ramalina species

Ramalina maciformis and Ramalina lacera were exposed to different solutions and UV-B to seek for alterations in the PSII photosynthetic quantum yield (F(v)/F(m)), in response to chemicals and radiation. For R. maciformis, significant alterations of the F(v)/F(m) ratio occurred only in response to different bisulphite solutions. The F(v)/F(m) ratio decreased most in R. maciformis and R. lacera following exposure to 5 and 1 mM bisulphite, respectively. Significant differences in F(v)/F(m) ratios were observed for R. lacera in response to different solutions and light at different wavelengths, this being synergistic. The PSII system was unaffected by simulated acid rain in both lichens. R. maciformis, in particular, may survive limited acid rain exposure owing to high Ca oxalate accumulation. The F(v)/F(m) ratio decreased most in R. lacera following short-term exposures to CuSO(4), suggesting that this species is more sensitive to Cu ions under acidic conditions.     

Biohydrogen production through fermentation using liquid swine manure as substrate

In this paper, continuous production of hydrogen through fermentation with liquid swine manure as substrate was researched using a semi-continuously fed fermenter (8 L in total volume and 4 L in working volume). The pH and temperature for the fermenter were controlled at 5.3 +/- 0.1 and 35 +/- 1 degrees C, respectively, throughout the experiment. Three hydraulic retention times (16, 20, and 24 h) were investigated for their impact on the efficiency and performance of the fermenter in terms of hydrogen yields. The results indicate that hydraulic retention time (HRT) has a strong influence on the fermenter performance. An increasing HRT would increase the variation in hydrogen concentration in the offgas. To produce hydrogen with a fairly consistent concentration, the HRT of the fermenter should not exceed 16 h, which, however, did not appear to be short enough to control methanogenesis because the offgas still contained about 5% methane. When methane content in the offgas exceeded 2%, an inverse linear relationship between hydrogen and methane was observed with a correlation coefficient of 0.9699. To increase hydrogen content in the offgas, methane production has to be limited to below 2%. Also, keeping oxygen content in the fermenter below 1.5% would increase the hydrogen concentration to over 15%. The product to substrate ratio was found to be around 50% for the fermenter system studied, evidenced by the observation that for every 6 liters of manure fermented, 3 liters of pure hydrogen were produced, which was significant and encouraging.